I had a previous install of BFW and uninstalled it from control panel before installing steam's version. Additionally, when I install add-ons or change my preferences, the files are placed straight into the drive. E.g: W:\preferences instead of installing the files properly. This also means that add-ons will not run.
Any ideas?

I had this problem to, i solved mine by going into Onedrive/Documents/My Games and then making a new folder named "Wesnoth1.14". I don't know if this is for sure solution but it worked for me so i decided to put it here.